1. Field of the Invention
The present invention relates to a porous carbon structure, a method of preparing the same, an electrode catalyst for a fuel cell, an electrode for a fuel cell, and a membrane-electrode assembly for a fuel cell. More particularly, the present invention relates to a porous carbon structure having high electronic conductivity and a large specific surface area, a method of preparing the same, an electrode catalyst for a fuel cell, an electrode for a fuel cell, and a membrane-electrode assembly for a fuel cell.
2. Description of the Related Art
A porous material is defined as a material formed with pores, and it is classified as microporous having a pore size of less than 2 nm, mesoporous having a pore size ranging from 2 to 60 nm, and macroporous having a pore size of more than 60 nm. Generally, a porous material can be applicable to various fields such as for a catalyst carrier, a separation system, a low dielectric constant material, a hydrogen saving material, a photonix crystal, and so on.
The porous material may include an inorganic material, a metal, a polymer, and a carbon-based material. Among them, the carbon-based material is a useful material applicable to various fields since it has excellent chemical, mechanical, and thermally stable characteristics.
Particularly, the porous carbon material can be widely applicable to a fuel cell field since it has excellent ion conductivity, anti-corrosion, cost saving, and surface characteristics. Various porous carbon materials are applied in the fuel cell field. Representative examples thereof include activated carbon and carbon black for a catalyst carrier. More specifically, an electrode catalyst carrier of a fuel call includes carbon black or Vulcan XC-72. The commercially available E-TEK catalyst includes a catalyst in which Pt—Ru alloy is supported in Vulcan XC-72.
Recently, different kinds of carbon materials such as meso-structure carbon, graphitic carbon nanofiber, and mesocarbon microbeads have widely been used as a catalyst supporter to improve metal catalyst activity. However, it is still difficult to synthesize a porous carbon material having a large specific surface area and an interconnection structure.
In addition, it is possible to synthesize a regularly arranged porous carbon material by a template duplication method using zeolite, a mesoporous material, and colloidal crystal. This synthesis method is used to provide a porous carbon material by injecting a carbon precursor into a solid porous silica mold, carbonizing the carbon precursor under a non-oxidation condition, and dissolving the silica mold in a HF or NaOH solution to provide a porous carbon material. However, it is difficult to increase the specific surface area of a carbon material having similar size pores. Accordingly, studies on porous carbon materials having an interconnection structure are still required.